US20110273072A1 - Light bulb - Google Patents

Abstract

A light bulb includes an enclosure, a heat-dissipating unit, and a lamp unit. The enclosure extends along an axis, and defines an inner space therein. The heat-dissipating unit includes a hollow first heat-dissipating element disposed in the inner space, a second heat-dissipating element surrounded by the first heat-dissipating element and extending along the axial direction, and an end heat-dissipating element mounted to the second heat-dissipating element at a distal end thereof. The lamp unit includes a first circuit board disposed at a periphery of the first heat-dissipating element, a second circuit board mounted on the end heat-dissipating element, and a plurality of light-emitting elements mounted on the first and second circuit boards for emitting light beams.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application claims priority of Taiwanese application No. 099114790, filed on May 10, 2010 and Taiwanese application No, 099117571, filed on Jun. 1, 2010.
BACKGROUND OF THE INVENTION
• 1. Field of the Invention
• The invention relates to a light bulb, more particularly to a light bulb capable of dissipating heat that is generated during use.
• 2. Description of the Related Art
• Referring toFIGS. 1 and 2, Taiwanese Patent No. M377525 discloses aconventional light bulb1 comprising abase circuit board11, a plurality of extendingcircuit boards12 electrically connected to thebase circuit board11, a plurality of light-emitting diodes (LEDs)13 mounted on the extendingcircuit boards12, anenclosure14 receiving thebase circuit board11, the extendingcircuit boards12, and theLEDs13 therein, and an externally threadedlamp seat15 coupled to theenclosure14, electrically connected to thebase circuit board11, and disposed for engaging threadedly a lamp socket (not shown).
• Though the above-mentionedlight bulb1 can provide illumination, heat generated by components of thelight bulb1 cannot be dissipated effectively and may damage theLEDs13. Therefore, the service life of theconventional light bulb1 is relatively short.
SUMMARY OF THE INVENTION
• Therefore, the object of the present invention is to provide a light bulb that can dissipate heat generated during use and that is durable.
• According to the present invention, there is provided an light bulb including an enclosure, a heat-dissipating unit, and a lamp unit. The enclosure extends along an axis, defines an inner space therein, and has an open end registered with the axis. The heat-dissipating unit includes a hollow first heat-dissipating element that is disposed in the inner space of the enclosure, a second heat-dissipating element that is surrounded by the first heat-dissipating element, that extends along the axial direction, and that cooperates with the first heat-dissipating element to define a heat-dissipating compartment therebetween, and an end heat-dissipating element that is mounted to the second heat-dissipating element at a distal end thereof distal from the open end of the enclosure. The lamp unit includes a first circuit board disposed at a periphery of the first heat-dissipating element, a second circuit board mounted on the end heat-dissipating element at one side opposite to the open end along the axis, and a plurality of light-emitting elements mounted on the first and second circuit boards for emitting light beams.
BRIEF DESCRIPTION OF THE DRAWINGS
• Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, of which:
• FIG. 1 is a partly exploded perspective view of a conventional light bulb;
• FIG. 2 is a perspective view of the conventional light bulb;
• FIG. 3 is an exploded perspective view of a first preferred embodiment of a light bulb according to the present invention;
• FIG. 4 is an exploded sectional view of the first preferred embodiment;
• FIG. 5 is a sectional view of the first preferred embodiment;
• FIG. 6 is e sectional view of a second preferred embodiment of the light bulb according to the present invention;
• FIG. 7 is an exploded perspective view of a third preferred embodiment of the light bulb according to the present invention;
• FIG. 8 is an exploded sectional view of the third preferred embodiment; and
• FIG. 9 is a sectional view of the third preferred embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
• Before the present invention is described in greater detail, it should be noted that like elements are denoted by the same reference numerals throughout the disclosure.
• FIGS. 3 to 5 show a first preferred embodiment of a light bulb according to the present invention. The light bulb comprises anenclosure2, a heat-dissipating unit3, a lamp unit4, and a surroundingseat5.
• Theenclosure2 is made of glass and shaped as the bulb. Theenclosure2 extends along an axis (X), and has anopen end201 that is registered with the axis (X), an innerperipheral surface24 that defines aninner space20 therein, and afluorescent coating25 that is applied on the innerperipheral surface24.
• The heat-dissipating unit3 includes a hollow first heat-dissipatingelement31 that is disposed in theinner space20 of theenclosure2, a second heat-dissipatingelement32 that is surrounded by the first heat-dissipating element31, that extends along the axial direction (X), and that cooperates with the first heat-dissipating element31 to define a heat-dissipating compartment38 therebetween, and an end heat-dissipating element34 that is mounted to the second heat-dissipatingelement32 at adistal end321 thereof that is distal from theopen end201 of theenclosure2 along the axis (X).
• In this embodiment, the heat-dissipating unit3 further includes six angularly spaced-apart heat-dissipating connectors33 that interconnect the second heat-dissipatingelement32 and the first heat-dissipating element31, a heat-conductive washer35 that is disposed between the end heat-dissipatingelement34 and the second heat-dissipating element32, and afastening member36 that secures fixedly the end heat-dissipating element34 and the heat-conductive washer35 to the second heat-dissipatingelement32. The heat-dissipating unit3 further includes a third heat-dissipatingelement37 that hasinner end375 connected to the first heat-dissipating element31, and anouter end376 extending outwardly of theopen end201 of theenclosure2, thereby permitting heat conduction from the first heat-dissipatingelement31 to the third heat-dissipating element37. It should be noted that the first and third heat-dissipating elements31,37 may be formed integrally in other embodiments of this invention.
• In this embodiment, the first and second heat-dissipating elements31,32, and the heat-dissipating connectors33 are made of heat-conductive material, such as aluminum, and are formed integrally. The end heat-dissipatingelement34, the heat-conductive washer35, and the third heat-dissipatingelement37 are also made of aluminum. The fasteningmember36 is configured as a screw and is also made of a heat-conductive material. Therefore, heat conduction between the above-mentioned elements is permitted.
• The first heat-dissipating element31 is formed as a hollow hexagonal prism, and has amounting portion311 that is adjacent to theopen end201 of theenclosure2, and that is formed with a plurality ofmounting holes312. The third heat-dissipatingelement37 has amounting portion371 at theinner end375. Themounting portion371 has a shape corresponding to and is sleeved fittingly on themounting portion311 of the first heat-dissipatingelement31. Themounting portion371 of the third heat-dissipatingelement37 is formed with a plurality ofmounting holes373 that are aligned respectively with themounting holes312 of the first heat-dissipatingelement31. The third heat-dissipatingelement37 and the first heat-dissipatingelement31 are connected fixedly to each other by a plurality ofscrews378 extending though themounting holes312,373. It should be noted that the first heat-dissipatingelement31 may be shaped as a polygonal prism or a cylinder in other embodiments of this invention.
• The lamp unit4 is mounted to the heat-dissipating unit3 and includes afirst circuit board41 that is a flexible printed circuit board surrounding the first heat-dissipating element31, asecond circuit board42 that is mounted on the end heat-dissipating element34 at one side opposite to theopen end201 along the axis (X), and a plurality of light-emitting elements43 that are mounted on the first andsecond circuit boards41,42 for emitting light beams converting circuit
• The light-emittingelements43 of the lamp unit4 are light-emitting diodes (LEDs) that are economical in terms of power consumption thereby rendering the light bulb of this invention an energy-saving light bulb. The light-emitting elements43 also provide a high illumination intensity, and that are arranged on the first andsecond circuit boards41,42 so as to provide a 360° illumination. Further, composition of thefluorescent coating25 applied on the innerperipheral surface24 is selected to be excited by the ultraviolet radiation of the light-emittingelements43, and converts light beams emitted by the light-emittingelements43 to output uniform illumination. For example, when the LEDs emit blue light, the selected composition of thefluorescent coating25 may convert the blue light into natural light.
• The light bulb of this invention further comprises ahollow contact unit6 including a contact body that has an internally threadedsurface61 defining areceiving space60 therein, and an externally threadedsurface62 opposite to the internally threadedsurface61, and that is formed with anopening64 forward theopen end201 of theenclosure2 and a plurality of heat-dissipating holes63 (only one is visible) formed at a rear end of thehollow contact unit6 that is distal from theopen end201 of theenclosure2. The third heat-dissipatingelement37 further has an externally threadedportion374 at theinner end376 thereof and extending into thereceiving space60 through theopening64 to engage the internally threadedsurface61 of thecontact unit6 so as to permit heat conduction therebetween. Thehollow contact unit6 is able to engage threadedly a commercially available lamp socket (not shown) so as to provide electric power for the light-emittingelements43. The third heat-dissipatingelement37 may be in other kinds of contact engagement with thecontact unit6 in other embodiments of this invention.
• The AC/DC converting circuit44 is mounted in the third heat-dissipating element37 and includes a circuit board (not shown) and conductive wires (not shown) connected to thehollow contact unit6 and the first andsecond circuit boards41,42. Since the feature of this invention does not reside in the AC/DC converting circuit44, further details of the same are omitted herein for the sake of brevity.
• The surroundingseat5 has a connectingpart51 sleeved on the third heat-dissipating element37 and a surroundingpart52 extending outwardldy and obliquely from the connectingpart51 and having an inner diameter that increases toward theopen end201 of theenclosure2. Theenclosure2 has an open section21 defining theopen end201 and extending between the connecting part of the surroundingseat5 and the third heat-dissipating element37. The third heat-dissipatingelement37 is formed with anannular protrusion377 that cooperates with a front and of the contact body of thecontact unit6 adjacent to theopening64 to define aclamping groove379 therebetween. The connectingportion51 of the surroundingseat5 is retained in theclamping groove379 so as to be positioned relative to the third heat-dissipatingelement37. As such, the third heat-dissipatingelement37 can also serve as a positioning seat so as to position the first heat-dissipatingelement31 relative to theenclosure2.
• Heat generated by the light-emittingelements43 during use of the light bulb of this invention is conducted to the first and end heat-dissipatingelements31,34 through the first andsecond circuit boards41,42, and is further conducted to the second heat-dissipatingelements32 through the heat-conductive washer35 and the heat-dissipating connectors33. Moreover, heat can also be conducted from the first heat-dissipatingelement31 to the third heat-dissipatingelement37 so as to be dissipated outwardly of theenclosure2. Heat generated by the lamp socket can also be conducted to the third heat-dissipatingelement37 through thecontact unit6. Therefore, heat can be dissipated efficiently.
• Additionally, a heat-conductive insulator (not shown) may be disposed between the third heat-dissipatingelement37 and thehollow contact unit6, such that the third heat-dissipatingelement37 is electrically-insulated from thehollow contact unit6. Similarly, heat-conductive insulators may also be disposed between the first heat-dissipatingelement31 and thefirst circuit board41, and between the end heat-dissipatingelement34 and thesecond circuit board42.
• Referring toFIG. 6, a second preferred embodiment of the light bulb according to the present invention has a structure similar to that of the first embodiment. The main difference between this embodiment and the first embodiment resides in that theenclosure2 is configured as a tube that has a uniform diameter.
• Referring toFIGS. 7 to 9, a third preferred embodiment of the light bulb according to the present invention has a structure similar to that of the first embodiment. The main difference between this embodiment and the first embodiment resides in the following. In this embodiment, the heat-conductive connectors33 as illustrated in the first preferred embodiment are omitted, and the first and second heat-conductive elements31,32 are spaced apart from each other in a radial direction that is transverse to the axis (X). The heat-dissipatingunit3 further includes first and second heat-insulatingmembers30,30′, awasher39, and first andsecond fastening members36,36′.
• The first heat-insulatingmember30 has acontact segment302 that is coupled directly to aproximate end314 of the first heat-dissipatingelement31 corresponding to aproximate end322 of the second heat-dissipatingelement32 that is opposite to thedistal end321 thereof along the axis (X) and that is proximate to theopen end201 of theenclosure2, and aseparating segment301 that from thecontact segment302 extends in the axial direction (X) between the first and second heat-dissipatingelements31,32. The second heat-insulatingmember30′ is disposed between the end heat-dissipatingelement39 and a combination of the first and second heat-dissipatingelements31,32. The second heat-insulatingmember30′ has acontact segment302′ that is coupled directly to adistal end313 of the first heat-dissipatingelement31 corresponding to thedistal end321 of the second heat-dissipatingelement32, and aseparating segment301′ that extends from thecontact segment302′ in the axial direction (X) between the first and second heat-dissipatingelements31,32. The separatingsegments301,301′ are spaced apart from the second heat-dissipatingelement32 in the radial direction, such that agaps380 is formed between the first heat-insulatingmember30 and the second heat-dissipatingelement32, and that agap380′ is formed between the second heat-insulatingmember30′ and the second heat-dissipatingelement32. Thegaps380,380′ are in fluid communication with the heat-dissipating compartment38 (seeFIG. 9).
• Thewasher39 is mounted to theproximate end322 of the second heat-dissipatingelement32 and the first heat-insulatingmember30. Therefore, the end heat-dissipatingelement34, thewasher39, and the second heat-dissipatingelement32 are heat-insulated from the first heat-dissipatingelement31. The heat-insulatingmembers30,30′ may be made of silica gel or other heat-insulated material.
• The end heat-dissipatingelement34 and thewasher39 are formed respectively with a plurality of spaced apart heat-dissipatingholes341,391 that are in fluid communication with the heat-dissipatingcompartment38. Thesecond circuit board42 is also formed with a plurality of heat-dissipating holes (not shown) in fluid communication with the heat-dissipatingholes391. Thefirst fastening member36 secures thewasher39 to theproximate end322 of the second heat-dissipatingelement32. Thesecond fastening member36′ secures thesecond circuit board42 and the end heat-dissipatingelement34 to thedistal end321 of the second heat-dissipatingelement32.
• By virtue of the heat-insulatingmembers30,30′ heat conduction from thefirst circuit board41 to the first heat-dissipatingelement31, and from thesecond circuit board42 to the second heat-dissipatingelement32 through the end heat-dissipatingelement34 will result in a temperature difference between the first and second heat-dissipatingelements31,32, thereby conducting a heat convection in the heat-dissipatingcompartment38. Further, heated air in the heat-dissipatingcompartment38 exchanges heat with air outside the heat-dissipatingcompartment38 through thegaps380,380′ so as to facilitate heat-dissipating effect of the heat-dissipatingunit3.
• To sum up, the advantages of the present invention are as follows. The light-emittingelements43 of the lamp unit4 are arranged on the first andsecond circuit boards41,42 to provide a 360° illumination. Moreover, heat generated by the light-emittingelements43 and other components of the light bulb during use can be conducted to the first and second heat-dissipatingelements31,32, and then be dissipated outwardly of theenclosure2 either through the third heat-dissipatingelement37 or through thegaps380,380′ (as illustrated in the third embodiment). Therefore, the heat-dissipating ability of the light bulb is increased, such that the service life of the light bulb of this invention is lengthened.
• While the present invention has been described in connection with what are considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.

Claims (11)

1. An light bulb comprising:

an enclosure extending along an axis, defining an inner space therein, and having an open end that is registered with the axis;

a heat-dissipating unit including

a hollow first heat-dissipating element that is disposed in said inner space of said enclosure,

a second heat-dissipating element that is surrounded by said first heat-dissipating element, that extends along the axial direction, and that cooperates with said first heat-dissipating element to define a heat-dissipating compartment therebetween, and

an end heat-dissipating element that is mounted to said second heat-dissipating element at a distal end thereof that is distal from said open end of said enclosure; and

a lamp unit including a first circuit board that is disposed at a periphery of said first heat-dissipating element, a second circuit board that is mounted on said end heat-dissipating element at one side opposite to said open end along the axis, and a plurality of light-emitting elements that are mounted on said first and second circuit boards for emitting light beams.

2. The light bulb as claimed inclaim 1, wherein said heat-dissipating unit further includes at least one heat-dissipating connector that interconnects said first and second heat-dissipating elements.

3. The light bulb as claimed inclaim 2, wherein said heat-dissipating unit further includes a fastening member that secures fixedly said end heat-dissipating element to said second heat-dissipating element.

4. The light bulb as claimed inclaim 1, wherein said heat-dissipating unit further includes a fastening member that secures fixedly said end head-dissipating element to said second heat-dissipating element.

5. The light bulb as claimed inclaim 1, wherein said first and second heat-dissipating elements are spaced apart from each other in a radial direction that is transverse to the axis.

6. The light bulb as claimed inclaim 5, wherein said heat-dissipating unit further includes:

a first heat-insulating member having a contact segment that is coupled to a proximate end of said first heat-dissipating element corresponding to a proximate end of said second heat-dissipating element that is opposite to said distal end thereof along the axis and that is proximate to said open end of said enclosure, and a separating segment that extends from said contact segment of said first heat-insulating member in the axial direction between said first and second heat-dissipating elements;

a second heat-insulating member disposed between said end heat-dissipating element and a combination of said first and second heat-dissipating elements, said second heat-insulating member having a contact segment that is coupled to a distal end of said first heat-dissipating element corresponding to said distal end of said second heat-dissipating element, and a separating segment that extends from said contact segment of said second heat-insulating member in the axial direction between said first and second heat-dissipating elements;

a washer mounted to said proximate end of said second heat-dissipating element and said first heat-insulating member, said end heat-dissipating element and said washer being formed with a plurality of spaced apart heat-dissipating holes that are in fluid communication with said heat-dissipating compartment;

a first fastening member securing said washer to said proximate end of said second heat-dissipating element; and

a second fastening member securing said second circuit board and said end heat-dissipating element to said distal end of said second heat-dissipating element.

7. The light bulb as claimed inclaim 1, wherein said heat-dissipating unit further includes a third heat-dissipating element that has an inner end connected to said first heat-dissipating element, and an outer end extending outwardly of said open end of said enclosure, thereby permitting heat conduction from said first heat-dissipating element to said third heat-dissipating element.

8. The LIGHT BULB as claimed inclaim 7, further comprising a hollow contact unit that has an inner surface defining an receiving space, said outer end of said third heat-dissipating element extending into said receiving space and being in contact with said inner surface.

9. The LIGHT BULB as claimed inclaim 7, wherein said first heat-dissipating element has a mounting portion adjacent to said open end of said enclosure, said third heat-dissipating element having a mounting portion that is sleeved fittingly on said mounting portion of said first heat-dissipating element.

10. The light bulb as claimed inclaim 1, wherein said first heat-dissipating element is a hollow polygonal prism, said first circuit board being a flexible printed circuit board surrounding said first heat-dissipating element, said light-emitting elements of said lamp unit being light-emitting diodes.

11. The light bulb as claimed inclaim 1, wherein said enclosure further has an inner peripheral surface defining said inner space, and a fluorescent coating applied on said inner peripheral surface.

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